Commit e86c8186d0 ("platform/x86:intel/pmc: Enable the ACPI PM Timer to
be turned off when suspended") can cause the suspend process to hang as
the pmcdev->lock in the pmc_core_acpi_pm_timer_suspend_resume might already
be held by the pmc_core_mphy_pg_show or pmc_core_pll_show if the userspace
gets frozen when these functions are being executed.
Also, pmc_core_acpi_pm_timer_suspend_resume must not sleep, as this
function is called indirectly by the tick_freeze function in
kernel/time/tick-common.c, which holds the spinlock.
Revert the changes for now to fix these issues.
Fixes: e86c8186d0 ("platform/x86:intel/pmc: Enable the ACPI PM Timer to be turned off when suspended")
Reported-by: Luca Coelho <luca@coelho.fi>
Closes: https://lore.kernel.org/lkml/40555604c3f4be43bf72e72d5409eaece4be9320.camel@coelho.fi/
Signed-off-by: Marek Maslanka <mmaslanka@google.com>
Link: https://lore.kernel.org/r/20241012182656.2107178-1-mmaslanka@google.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Allow to disable ACPI PM Timer on suspend and enable on resume. A
disabled timer helps optimise power consumption when the system is
suspended. On resume the timer is only reactivated if it was activated
prior to suspend, so unless the ACPI PM timer is enabled in the BIOS,
this won't change anything.
The ACPI PM timer is used by Intel's iTCO/wdat_wdt watchdog to drive the
watchdog, so it doesn't need to run during suspend.
Signed-off-by: Marek Maslanka <mmaslanka@google.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240812184208.1080710-1-mmaslanka@google.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
